The invention relates to a downrigger apparatus for spooling a weight line carrying a weight, which releasably positions a fishing lure on a separate fishing line at a desired depth in water for trolling.
Prior art downrigger apparatus are known and are commonly carried on the gunwale of a vessel to suspend a heavy weight at the end of a weight line extending from the downrigger. The line is wound on or off a spool of the downrigger, either manually or using electrical power. There are usually hundreds of feet of line wound on the downrigger spool, and as the weight can be between 10 and 15 pounds, considerable time and effort can be expended in manually winding the weight upwards to position the fishing lure at shallower depths, or to wind in the weight when fishing in a particular location is finished, or to inspect or change the fishing lure. If one operator is in control of several downriggers, it can be difficult to raise the weights of all downriggers quickly, for example after a fish has taken the hook, or the boat is unexpectedly approaching shallower water. In either case it is usual to raise all the downriggers as quickly as possible, either to prevent entangling the fishing line on the weight lines, or to prevent the weight from contacting the bottom of the body of water as described below.
When fishing close to an uneven sea bed or lake bottom, the weight can become fouled or "hung up" in rocks, water-logged logs, or other debris on the bottom which initially prevents winding up the weight, or prevents further progress of the vessel. If the weight is to be wound up manually, excessive winding load is experienced by the operator, who would then normally reposition the vessel in such a way as to pull the weight free, thus enabling the weight to be wound upwards freely. It is usually easy for the manually winding operator to detect when the weight is hung up and immediate corrective action can usually be taken. Difficulties can arise when the weight of an electrically powered downrigger is hung up as the hang-up may not be immediately obvious.
Some prior art manually operated downriggers require two-handed operation, namely one hand for winding the spool, and the other hand for operating a manually actuated brake to brake the spool carrying the line. When the weight attains a desired depth, the brake is actuated to hold the weight at that depth. In the present Applicant's U.S. Pat. No. 4,044,968, means are shown to provide an automatic downrigger brake which is actuated automatically when the spool commences to unwind. This enables one-handed operation of the downrigger, as the brake is automatically applied as soon as the operator permits the spool to unwind a few degrees. Alternatively, the brake of the Applicant's patent can be applied directly using the other hand to lock the spool. This patented device has a brake member which is moved into engagement with the reel by a pair of spaced rollers which act as cams by engaging a pair of similar helical surfaces of the brake member. Rotation of the spool when unwinding line from the spool can automatically move the brake member into engagement with the spool, thus braking the spool against rotation. While the rollers and helical surfaces of this patented structure are adequate for manual operation, difficulties would likely be encountered if this type of automatic brake were used with an electrically powered downrigger.
Some electrically powered downriggers known to the inventor incorporate a worm and worm wheel gear reduction assembly to reduce r.p.m. of the spool with respect to the motor. In some of these devices, a direct brake on the spool is not provided to prevent unwinding of the spool. Instead, some apparatus use the so-called "self-locking ability" of the worm gear and worm wheel. Theoretically, a worm gear will not "back drive" or be "reverse driven" if the friction angle is greater than the worm lead angle, and this self-locking ability has been used in many applications incorporating worm gears and worm wheel assemblies. However, for use with downriggers, where fluctuating loads are experienced, self-locking ability of the worm wheel is not reliable, and inadvertent unwinding of the reel can take place with this type of indirect braking due to the fluctuating loads. Furthermore, use of the gears to prevent inadvertent unwinding, as opposed to a direct spool brake, subjects the gears to additional, non-driving load, aggravating wear and sometimes causing premature failure. No electrical downriggers known to the inventor have automatic direct braking of the spool when the motor stops, and thus a separate manual action is required to brake the spool when the motor stops. A further alternative would be to use the resistance to back-driving of the motor to prevent the reel from inadvertantly winding out the line.
Furthermore, some electrical downriggers that rely on the gear reduction between the motor and the spool to prevent the spool from unwinding have to be driven in reverse to lower the weight, i.e. the weight is "powered down". A reversing switch for the motor is required, and the speed of lowering the weight is usually very close to the speed of raising the weight, unless a variable motor speed control is supplied, or the gear ratio can be changed to permit faster lowering of the weight than raising of the weight. If the weight must be lowered by "powering down" using the motor, the motor is subjected to twice as much wear as would be the case where a weight can be lowered without powering down.
With electrical downriggers it is known to provide an overload device which prevents overloading of the electric motor during winding in, should the weight hang up on the bottom which would prevent the reel from rotating to wind up the line. Such overload devices include circuit breakers and/or thermal switches in the motor, which are responsive to excessive current and/or to heat generated in the electric motor. Some devices include friction clutches which slip when a threshold torque applied by the motor is exceeded. None of these overload devices are totally satisfactory as the operator is not usually aware that an overload situation has occurred, unless he is closely monitoring rotation of the reel. Consequently, when a motor overload situation arises with a prior art apparatus, the motor might be damaged if the overload device is not properly activated, or the friction clutch can slip for sometime before it is noticed and can become overheated, possibly causing permanent damage. To the inventor's knowledge, no downrigger overload devices are provided which generate an audible signal to warn the operating than an overload situation has occurred.